The transformation of cholesterol to pregnenolone by preparations of mitochondria from different endocrine glands will be studied qualitatively and quantitatively. Specifically, we will test the existence of 20-dehydrocholesterol and of 20,22-oxidocholesterol as intermediates in the catabolism of cholesterol to pregnenolone. Compartmentalization during the transformation of cholesterol yields pregnenolone will be studied with labeled molecules (tribitum and carbon-14). 22,22-Dimethylcholesterol will be produced and tested as inhibitors of cholesterol and corticoid production. BIBLIOGRAPHIC REFERENCES: Acid-catalyzed rearrangement of 20-vinylpregn-5-ene-3 beta,20-diol 3-acetate. Y. Letourneux, M.M.L. Lo, N. Chaudhuri and M. Gut. J. Org. Chem. 40: 516, 1975. Abnormal products obtained during an attempted substitution of 3 alpha, 5-cyclo-6 beta-methoxy-5 alpha 23,24-bisnorcholan-22-o1 tosylate with a Grignard reagent involving gamma,gamma-dimethylallyl bromide. S.K. Dasgupta and M. Gut. J. Org. Chem. 40: 1475, 1975.